The present invention relates to the field of hand tools such as are used for holding and turning collars, and more particularly, to spanner wrenches and vice-grip pliers.
Power in distribution facilities is commonly supplied by 600 ampere underground electrical lines at 7,200 volts or more. Underground insulated connections and taps are typically made within mechanically and electrically sealed rubber xe2x80x9cTxe2x80x9d bodies. The insulation is skived from a gauged length of the wire conductor at the end of the electrical cable and a lug is crimped tightly onto the conductor. A tight fitting boot, known as a cable adaptor, is pushed over the cable insulation using silicone sealer both for lubrication and electrical insulation. The assembly is then pushed into the middle leg of a rubber xe2x80x9cTxe2x80x9d body, using the silicone sealer, first to lubricate, then to seal and insulate the joint. The rubber xe2x80x9cTxe2x80x9d body is internally keyed to orient the junction eye for a threaded stud inserted axially through the running legs of the xe2x80x9cTxe2x80x9d body. A connector plug with an internally threaded axial insert is screwed on each end of the threaded stud. Each connector plug has a shouldered body with two symmetrical ends, sized to fit closely within the inside diameter of a xe2x80x9cTxe2x80x9d body. The shoulders are located to come against the end of a xe2x80x9cTxe2x80x9d body running leg as the connector plug bottoms against the lug. A hard cylindrical ceramic collar located between the shoulder lands has lug engaging holes set 180xc2x0 apart so that the connector plug can be tightened with a conventional spanner wrench having a curved head with a lug at one end for fitting into a lug engaging hole. As the opposed connector plugs are tightened on the threaded stud, the lug is clamped tightly between the two plug ends and the shoulders seal against the xe2x80x9cTxe2x80x9d body. Here again, the joint is sealed and insulated with the silicone sealer.
In the same manner, another xe2x80x9cTxe2x80x9d body may be joined at the open end of a connector plug, to provide a 200 ampere tap or make a 600 ampere line connection. When an electrical connection is not desired at a xe2x80x9cTxe2x80x9d body running leg a basic insulation plug is used for closure, instead of a connector plug. Thus, any number of sealed, electrically insulated connections and taps may be provided in an underground electrical line.
When made with the necessary hardness, the ceramic collars are also brittle. As a result, the spanner lug must be fully engaged and the heel of the wrench seated against the surface of the collar so as keep the wrench engaged and allow the application of torsional forces. Otherwise, the ceramic is easily chipped or broken. This is a persistent problem, and frequently, the damage is so severe that the connection must be taken apart in order to replace the broken connector plug.
Therefore, a first object of the present invention is to provide apparatus for positive engagement and tightening of spanner type collars. A second object is that this apparatus engage such collars in a manner that eliminates reliance on frictional forces for torque transmission to such collars. Yet a third object is that this apparatus engage such collars in a manner that eliminates the possibility of imposing a concentrated point load on the collar. Other objects are that the apparatus be easy to apply and use, adaptable to a range of collar sizes and inexpensive to manufacture. in general, and most importantly, for use with the relatively brittle, ceramic type spanner collars. Practice of the present inventions relates to or uses some steps and apparatus well known in the hand tool arts and therefore, not the subject of detailed discussion herein.
The present invention contemplates the aforementioned objectives with a wrench for engaging and turning spanner type threaded members. The wrench has a handle with an extended upper jaw member which terminates in a radiused 90xc2x0 arcuate portion. A cylindrical lug extends radially at the end of the radiused portion for engaging a spanner type threaded member and a clamping jaw member is pivotally connected to the handle so as to be diametrically opposed to the lug. The clamping jaw member is forced toward the upper jaw member to provide a diametrical clamping force on the threaded member and force the cylindrical lug into positive engagement.
In operation, the cylindrical lug is inserted radially into the engagement hole of a spanner type threaded member and the upper and clamping jaws are adjusted to apply diametrically opposed clamping forces to the threaded member at the generally cylindrical lug, so as to forcibly hold the lug in the engagement hole. A torsional force applied to the wrench forces cylindrical lug tangentially against a side of the engagement hole and the heel of the 90xc2x0 arcuate portion of the upper jaw bears radially against the periphery of the threaded member to react against the torsional force.